Differential Diagnosis in Dermatopathology

Insect "bite" vs. Lymphomatoid papulosis

A condition in which deposits of a fibrillary protein (amyloid) appear in the skin as macules, papules, and nodules consequent to the effects of local factors, or as patches (which may be purpuric), plaques, nodules, and tumors as a result of a syst…

Differential Diagnosis in Dermatopathology

Erythema multiforme vs. Graft-versus-host disease, acute phase

A condition in which deposits of a fibrillary protein (amyloid) appear in the skin as macules, papules, and nodules consequent to the effects of local factors, or as patches (which may be purpuric), plaques, nodules, and tumors as a result of a syst…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Anagen Effluvium?

“The follicle tends to respond in an all or none fashion with the notable exception of its response to cancer chemotherapy agents. This is the only known instance in which hair is lost follicles which continue in their growing phase without b…

Differential Diagnosis in Dermatopathology

Discussions

Lichen nitidus and lichen striatus are inflammatory diseases that mostly involve the upper part of the dermis and the epidermis. Both are characterized by a perivascular infiltrate of lymphocytes and histiocytes, lymphocytes and vacuolar alteration…

Histologic Diagnosis of Inflammatory Skin Diseases

Tuberculosis verrucosa cutis

…Findings histopathologic Fully developed Granulomas dotting a lichenoid infiltrate of lymphocytes and plasma cells Beneath the zone of lichenoid lymphoplasmacytic infiltration, discrete granulomas surrounded by numerous lymphocytes and plasma cells…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

…titis, infundibular, and perivascular dermatitis, psoriasiform lichenoid + 10.17.14B: Preponderance of neutrophils in the lichenoid infiltrate = Infection by atypical mycobacteria Acid-fast stain reveals countless bacilli in zones of suppuration…

Histologic Diagnosis of Inflammatory Skin Diseases

Images

Images 11.13.1A: Perivascular and interstitial dermatosis, infundibulocentric + 11.13.1B: Small lymphocytes, large abnormal lymphocytes, neutrophils and eosinophils = Lymphomatoid papulosis ¬†Episodically, as shown here, an infiltrate of l…

Histologic Diagnosis of Inflammatory Skin Diseases

Limitations of the Algorithmic Method

The algorithmic method proposed in these pages and predicated on patterns histopathologic is intended to be more than just a guide to diagnosis of particular pathologic processes in skin and subcutaneous fat; it is meant to serve as a springboard fo…

Resolving Quandaries in Dermatology, Pathology & Dermatopathology

Follicular Degeneration Syndrome?

…obvious clinically. The earliest findings observed by us are a lichenoid peri-infundibular infiltrate of lymphocytes followed by progressive peri-infundibular fibroplasia. As time goes on, the lichenoid infiltrate wanes and the fibrosis waxes, eventu…